Skalský, Ivo

Background : Modulation of the cardiac autonomic nervous system (ANS) is a promising adjuvant therapy in the treatment of atrial fibrillation (AF). In pre-clinical models, pulsed field (PF) energy has the advantage of selectively ablating the epicardial ganglionated plexi (GP) that govern the ANS. Objective: This study aims to demonstrate the feasibility and safety of epicardial ablation of the GPs with PF during cardiac surgery with a primary efficacy outcome of prolongation of the atrial effective refractory period (AERP). Methods : In a single-arm, prospective analysis, patients with or without a history of AF underwent epicardial GP ablation with PF during coronary artery bypass grafting (CABG). AERP was determined immediately pre- and post- GP ablation to assess cardiac ANS function. Holter monitors were performed to determine rhythm status and Heart Rate Variability (HRV) at baseline and at 1 month post-procedure. Conclusions : This study demonstrates the safety and feasibility of epicardial ablation of the GP using PF to modulate the ANS during cardiac surgery. Large, randomized analyses are necessary to determine whether epicardial PF ablation can offer a meaningful impact on the cardiac ANS and reduce AF. Results : Of 24 patients, 23 (96%) received the full ablation protocol. No device-related adverse effects were noted. GP ablation resulted in a 20.7% ± 19.9% extension in AERP (P < 0.001). Post-operative AF was observed in 7 (29%) patients. Holter monitoring demonstrated an increase in mean heart rate (74.0±8.7 vs 80.6±12.3, P=0.01). There were no significant changes in HRV. There were no study-related complications.

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EU Horizon 2020 SME Instrument. Background Epicardial ganglionated plexi (GP) play a significant role in the initiation and maintenance of atrial fibrillation. However, modulation of this effect, through GP ablation, has had limited success; outcomes being confounded by unnecessary atrial tissue ablation and inability to access and ablate all of the atrial GPs. Selective pulsed field ablation (PFA) of GPs, using epicardial access, provides the opportunity to better identify the role of GP ablation in the treatment of atrial fibrillation. Purpose This study aimed to assess the safety and feasibility of selective GP ablation in patients undergoing elective coronary artery bypass grafting (CABG). It was hypothesized that GP ablation would provide an acute extension of atrial tissue refractoriness, which constitutes its antiarrhythmic effect. Methods Using a monopolar, monophasic PFA system, atrial GPs were ablated in nineteen patients with or without atrial fibrillation, undergoing CABG. The Oblique Sinus GP, Right Superior GP, Transverse Sinus GP, Left Superior GP and Ligament of Marshall GP were each ablated with up to sixty PFA pulses of 1000 V amplitude and 100 µs pulse width. Atrial Effective Refractory Period (AERP) was measured before and after all GP ablations, at the left atrial appendage (LAA) and on the right atrium (RA). Patients were monitored through to discharge for post-operative atrial fibrillation (POAF). Results Complete ablation of the GPs was performed in nineteen patients (aged 63.4 ± 6.6 years, 63.1% male) immediately after sternotomy. Electric field pulses were ECG-gated, with energy delivery during the ventricular refractory period. All GP sites were successfully accessed and ablated; all patients progressed immediately to their planned elective surgery and were discharged on schedule. Procedure time, for all GP ablations and AERP measurements was in the range 35-45 minutes. Thirteen valid pre- and post-ablation datasets were obtained. AERP (LAA and RA combined) increased upon GP ablation on average by 23% (220 ± 46 ms pre-ablation versus 269 ± 59 ms post-ablation, p = 0.002). Four patients experienced POAF; there was no evident correlation between POAF and AERP data. Only three of the enrolled patients had a prior history of AF; none of these exhibited AF on 24-hour Holter monitoring at 3-month follow-up. Conclusions Selective epicardial PFA of GPs is feasible and safe. An acute increase in atrial tissue refractoriness is promising but further studies are required to see how this translates to longer term outcomes in symptomatic AF patients and in a percutaneous epicardial access setting.